Conventionally, circuit analyzing software executes a direct current analysis of a circuit-under-analysis to calculate voltage values of nodes within the circuit and executes an alternating current analysis or transient analysis, using the calculated voltage values as initial voltage values.
In the direct current analysis, to analyze the operation of the circuit, the circuit analyzing software performs analysis by setting the voltage value of a node within the circuit to a given voltage value and calculates the voltage value of the node, which represents one operational state of the circuit, corresponding to a case where the voltage value of the node within the circuit is set at the specified voltage.
As for related technologies, for example, there is a technology of executing circuit analysis to detect a non-convergent node at which the voltage value does not converge on a solution. For example, there is a technology of setting the average value of the voltage values that have converged on the solution at other nodes as the initial value and re-executing the circuit analysis, when the circuit analysis has been executed and a non-convergent node is detected. For example, there is a technology of executing the circuit analysis and performing the convergence determination by the last voltage value and the second to last voltage value with respect to the node. For example, there is a technology of seeking the solution of the voltage value by activating plural solvers of the Newton's method, the Damped-Newton's method, etc., in a given order until a given convergence condition is satisfied. For examples of such technologies, refer to Japanese Laid-Open Patent Publication Nos. H7-121578, H5-342294, H6-110959, and H9-179895.
In the above conventional technologies, however, since the voltage values of the nodes that represent each state of plural operational states of the circuit are calculated, it is difficult determine in the circuit, the node for which the voltage value should be set at a voltage value that differs from the given voltage value in the direct current analysis.